Level Of Salinity Tolerance Research Articles

Isolation and Identification of Halophilic Bacteria Isolated from Mangrove Soil in Blue Lagoon, Port Dickson, Negeri Sembilan

Halophiles bacteria are capable of tolerating and surviving in extreme salinity due to the special biological structure that it possesses. Classification of halophilic bacteria includes slight, moderate, and extreme halophiles which range from low to high concentrations of salt. Biotechnological products yielded from bacteria residing in saline environment are proven to be valuable in a few industries. The isolated halophilic bacteria may yield powerful biomolecules such as enzymes which can enhance plant development, hence boosting agricultural industries. However, the insufficient data related to halophiles available in Malaysia may reduce the potential use of these bacteria in related industries. The goal of this study is to isolate and identify the potential halophilic bacteria and to determine the tolerance of halophiles in different concentrations of salt. Collection of soil samples was done at the mangrove soil in Blue Lagoon, Port Dickson, Negeri Sembilan. Isolation and purification of halophiles was done on nutrient agar media supplemented with 3% salt. Next, Gram-staining was performed on 4 colonies of bacteria with different types of single colony appearances. Then, the selected bacteria with different colony and morphological characteristics were tested in nutrient broth supplemented with 0%, 3%, 10% and 20% of salt. Molecular identification was conducted which involved DNA extraction and Polymerase Chain Reaction. All 4 isolates selected were tested to be Gram-stain positive and possessed rod-shaped. The bacteria have various salinity tolerance levels which may be due to the presence of different enzymes produced in their cells. Gene sequences and phylogenetic tree were analyzed based on 16s rRNA sequences to identify the species of the isolates. At the end of the experiment, isolate 2A1 and 2A4 were identified as Bacillus sp., while isolate 2A2 and 2A3 were identified as Cytobacillus oceanisediminis.

Genetic variability for salinity tolerance of tomato (Solanum lycopersicon MILL.) genotypes determined by stress tolerance indices

BackgroundTomato is an important vegetable crop; however, salinity hampers its growth and yield-related traits. Different tomato genotypes significantly differ in their salinity tolerance; thus, selecting the tolerant genotypes could improve yield and productivity under saline environments. MethodsThis study investigated salinity tolerance of five tomato genotypes, i.e., ‘Pakit’, ‘Riogrande’, ‘Roma’, ‘Continental’, and ‘Nagina’ under 0-, 100-, 150- and 200-mM salinity levels. Data relating yield-related traits (plant height, shoot fresh and dry weights, number of fruits per plant, single fruit weight and fruit yield per plant) and nine different stress tolerance indices were employed to infer salinity-tolerance of the genotypes. ResultsIncreasing salinity levels negatively affected the yield-related traits of genotypes; however, genotypes exhibited varied tolerance to salinity. The better and the poor yield-related traits were noted under 0- and 200-mM salinity levels, respectively. Similarly, genotypes ‘Pakit’ and ‘Nagina’ recorded the highest and the lowest values of yield-related traits. The genotype ‘Pakit’ proved the most tolerant to tested salinity levels compared to the rest of the genotypes. The ‘Pakit’ genotypes had the highest stress tolerance index (0.19, 1.06 and 1.79) and the lowest relative change in yield (6.00, 32.59, and 55.75%) under all salinity levels. Principal component analysis biplot revealed that ‘Pakit’ genotypes had superior yield traits and tolerance indices. ConclusionThe genotype ‘Pakit’ exhibited a higher level of salinity tolerance (6 % yield reduction under 100 mM salinity compared to 27.67 % reduction in ‘Nagina’ genotype. Therefore, genotype ‘Pakit’ can be recommended for cultivation on low to moderate saline soils without significant yield losses. On the other hand, ‘Nagina’ genotype proved the most sensitive to salinity (27.67 %, 56.79 %, and 68.90 % yield reduction under 100-, 150-, and 200-mM salinity, respectively). Therefore, this genotype should not be cultivated on saline soils.

Advanced Mutant Line Developed from Fatemadhan Shows Salinity Tolerance at both Seedling and Reproductive Stages

The generation of high-yielding rice mutants and their assessment under salt stress offers a great possibility to isolate salt tolerant line(s) with desired trait of interest. Two separate experiments were conducted at the seedling and reproductive stages of rice to assess the level of salinity tolerance of few advanced high-yielding rice mutants. In the first experiment, rice seedlings were grown under hydroponic conditions and 14-day-old seedlings were subjected to salt stress (EC=10 dS/m; 7 days). Salt stress caused significant reduction in root and shoot length and biomass and leaf chlorophyll content; however, a little reduction was found in the mutant Line-1. In contrast, a sharp increase in shoot Na+/K+ ratio was found in all the genotypes except, Binadhan-10, FL-478 and the mutant Line-1, which exhibited little increased ratio. The second experiment involved exposure of plant to salt stress (EC=10 dS/m) for three weeks at the late booting stage in a sizable plastic tub filled with field soil. Salt stress resulted in a significant decrease in yield and yield attributing traits in all the genotypes except Binadhan-10. Grain yield per panicle was found significantly positive correlation with panicle length, the number of filled grains per panicle, and 100-seed weight under both control and salt stress conditions. Based on the studied traits and stress tolerance indices, Binadhan-10 and mutant Line-1 categorized as salt tolerant and rest of the genotypes were categorized as susceptible, which is also evident from the biplot of principal component analysis. Considering the results from both of the experiments, mutant Line-1 was found tolerant genotype at both seedling and reproductive stage. However, further studies are required to determine the genetic issues controlling the salinity tolerance in mutant Line-1 and the high-yield potential of mutant Line-65 under control condition in a way to develop salt tolerant and high-yielding rice varieties, respectively.

The Genetic Variability of Indonesian Local Foxtail Millet Accession Based on Agro-morphological Traits and Early Salinity Tolerance Evaluation Utilizing SiDREB2-based SNAP Marker

Foxtail millet (Setaria italica L. Beauv.) is a grain-producing crop with high nutritional benefits and adaptability to broad environmental conditions. Indonesian local foxtail millet accessions are valuable genetic resources for crop improvement of the species. This study aims to assess the biodiversity of Indonesian local foxtail millet accessions and estimate their salinity tolerance level utilizing the SiDREB2-based SNAP marker and early evaluation at the seedling stage. Our results showed that eight Indonesian local foxtail millet accessions, namely Toraja, Mauliru-2, Hambapraing, NTB-1, ICERI-5, ICERI-6, Botok-4, and Botok-10, had high variability based on agro-morphological traits. The Hambapraing and Mauliru-2 were the potential accessions with high yield estimates (2.33 ton.ha-1 and 1.93 ton.ha-1) and early harvest time (<110 DAT). ICERI-6 was indicated as a salinity-tolerant genotype based on the SiDREB2-based marker and early salinity evaluation at the seedling stage, while Toraja, Mauliru-2, NTB-1, and Botok-4 were categorized as sensitive genotypes. Germplasm variability and the estimated salinity tolerance level of Indonesian local foxtail millet accessions presented in this study serve as essential information in the foxtail millet breeding for high productivity, early harvest time, and salinity tolerant variety.

Marker Assisted Introgression of Saltol QTL into “APMS 6B” to Enhance Salt Tolerance at Seedling Stage of Rice (Oryza sativa L.)

APMS 6B which is highly sensitive to salinity was used as a recurrent parent to introgress Saltol QTL from FL-478. Two gene linked markers viz., RM8094 and RM10793 were used for used to confirm backcross generations for saltol QTL. Two successive backcrosses were attempted to transfer target alleles of Saltol from FL478 into APMS-6B. After backcross progrmme, the BC2F1 plants subjected to foreground selection by using gene specific markers, positive plants for target gene were selected and selfed to raise BC2F2 populations. Twenty BC2F2 plants were identified to be homozygous dominant for Saltol QTL and these BC2F2 lines were also screened in plastic trays using Yoshida solution at the seedling stage. A total of BC2F2 lines were confirmed for the target gene and displayed a high level of salinity tolerance without any symptoms on their leaves, with a score of ‘0’.

Polymorphic analysis of the OsHKT1;5 exon 1 gene region on seasonal rice varieties with salt tolerant capacity

Abstract. Nguyen TP, La HTG, Do TK, Tran DG. 2023. Polymorphic analysis of theOsHKT1;5exon 1 gene region on seasonal rice varieties with salt tolerant capacity. Biodiversitas 24: 4159-4165. In recent years, saline intrusion has caused serious damage to agricultural production in the Mekong Delta; therefore, research on salinity-tolerant rice varieties is necessary. This study was carried out to screen the salt tolerance capacity of 38 seasonal rice varieties in four concentrations of NaCl supplements, including 4‰, 6‰, 8‰, and 10‰ in comparison with IR28 and Pokkali checks according to IRRI (2021) methods. Eight rice cultivars in four levels of salinity tolerance (two varieties of each level) were selected to evaluate the nucleotide sequence polymorphism in the coding region of OsHKT1;5exon 1, comparedwith that of IR28 and Pokkali checkcultivars and Nipponbare referential variety. The results of salt tolerance screening showed that the salt concentration and the rate of reduction of plant height and root length were positively correlated. Nucleotide sequence polymorphism analysis of OsHKT1;5exon 1 indicated six nucleotide substitutions (SNP) at positions 382, 418, 551, 994, 1119, and 1152. Further analysis revealed thatfive SNPs were detected withthree missense mutations (P60A, R63H, and H255D) in salt tolerant check variety (Pokkali), three to four SNPs with one to two missense mutations H255D or P60A and H255D were observed in salt moderate tolerant varieties, while salt-sensitive varieties and sensitive check variety IR28 were observed with two SNPs and one missense mutation (H255D).

Evaluation of Different Salinity Levels on Growth Performance and Proximate Composition of WALLAGO ATTU

The study was conducted to determine the optimum level of salinity tolerance on the growth performance and proximate composition of Wallago attu fed with tilapia meat. The experimental fish were collected from River Chenab district Muzaffargarh and acclimatized for 14 days in freshwater before the experiment began. The fish were divided into five treatments: T1, T2, and T3 with salinity levels 4, 8 and 12-ppt respectively with a control group (T0) in freshwater. Each treatment had one replicate and fish were stocked at a density of 5 fish’s/aquarium in the Laboratory. Fish were fed 5% of their body weight with tilapia meat and water was exchanged regularly after every alternate day. The present study indicates the highest survival rate at 12-ppt and mortality was observed beyond this point. Non-significant changes in growth parameters viz; Feed intake, Feed conversion ratio, and Weight gain, were found in treatments and the control group. Additionally, proximate composition (moisture, ash content, protein and fat) showed significant changes (P<0.005) in groups. Water quality parameters were found within the acceptable range during the study period. The result suggests that W. attu is a suitable species for rearing in harsh water earthen lakes and emphasizes the importance of considering salinity levels and leads to innovation in sustainable aquaculture practices.

Inheritance of important metric traits of wheat (Triticum aestivum)

Development of salinity tolerant genotypes is important for sustaining wheat productivity in suppressive soils. The generation mean analysis of three bread wheat crosses viz., Lok 1 x Raj 3880, Job 666 x Kharchia 65 and Raj 1972 x Kharchia 65 under normal and saline-sodic environment revealed presence of both additive and non-additive gene effects in the inheritance of grain yield per plant and other contributing characters under both the environments. Among the digenic interactions, all three types of epistatic effects were involved in the inheritance of characters studied. Only duplicate gene interaction was present, wherever available. Hence, intermating in early generations and intense selection in later generations could be successfully adopted for breeding wheat varieties having appreciable salinity tolerance level.

CRISPR-Cas9-based precise engineering of SlHyPRP1 protein towards multi-stress tolerance in tomato.

Recently, CRISPR-Cas9-based genome editing has been widely used for plant breeding. In our previous report, a tomato gene encoding hybrid proline-rich protein 1 (HyPRP1), a negative regulator of salt stress responses, has been edited using a CRISPR-Cas9 multiplexing approach that resulted in precise eliminations of its functional domains, proline-rich domain (PRD) and eight cysteine-motif (8CM). We subsequently demonstrated that eliminating the PRD domain of HyPRP1 in tomatoes conferred the highest level of salinity tolerance. In this study, we characterized the edited lines under several abiotic and biotic stresses to examine the possibility of multiple stress tolerance. Our data reveal that the 8CM removal variants of HK and the KO alleles of both HK and 15T01 cultivars exhibited moderate heat stress tolerance. Similarly, plants carrying either the domains of the PRD removal variant (PR1v1) or 8CM removal variants (PR2v2 and PR2v3) showed better germination under osmosis stress (up to 200 mM mannitol) compared to the WT control. Moreover, the PR1v1 line continuously grew after 5 days of water cutoff. When the edited lines were challenged with pathogenic bacteria of Pseudomonas syringae pv. tomato (Pto) DC3000, the growth of the bacterium was significantly reduced by 2.0- to 2.5-fold compared to that in WT plants. However, the edited alleles enhanced susceptibility against Fusarium oxysporum f. sp. lycopersici, which causes fusarium wilt. CRISPR-Cas9-based precise domain editing of the SlHyPRP1 gene generated multi-stress-tolerant alleles that could be used as genetic materials for tomato breeding.

Effect of Saline Treatment on Seed Germination of Adzuki Beans

Salinity is one of the major causes of abiotic stress for plant development and growth worldwide, and affects crop yield significantly. To analyse the level of salinity tolerance among 'Ji Hong 20' (JH20), 'Jin Xiao Dou 5' (JXD5) and 'Jin Xiao Dou 6' (JXD6) adzuki bean cultivars, nine saline levels (0.0, 32.5, 65.0, 97.5, 130.0, 162.5, 195.0, 227.5 and 260.0 mmol L-1 NaCl) were applied during seed germination. Germination potentials and final germination percentages of all cultivars were significantly reduced by NaCl with the level at which germination was affected being dependent on cultivar. The JXD5 seeds had the highest germination index and vigour index at the same NaCl concentrations, followed by the JH20 and then JXD6 seeds. The shoot and root lengths of JH20 and JXD5 were significantly shorter at NaCl concentrations > 65.0 mmol L-1, while those of JXD6 were reduced at salinity > 32.5 mmol L-1. Quadratic regression models could well predict the germination percentage of JH20, JXD5 and JXD6 seeds under saline stress.

Novel Salinity-Tolerant Third-Generation Hybrid Rice Developed via CRISPR/Cas9-Mediated Gene Editing.

Climate change has caused high salinity in many fields, particularly in the mud flats in coastal regions. The resulting salinity has become one of the most significant abiotic stresses affecting the world's rice crop productivity. Developing elite cultivars with novel salinity-tolerance traits is regarded as the most cost-effective and environmentally friendly approach for utilizing saline-alkali land. To develop a highly efficient green strategy and create novel rice germplasms for salt-tolerant rice breeding, this study aimed to improve rice salinity tolerance by combining targeted CRISPR/Cas9-mediated editing of the OsRR22 gene with heterosis utilization. The novel alleles of the genic male-sterility (GMS) and elite restorer line (733Srr22-T1447-1 and HZrr22-T1349-3) produced 110 and 1 bp deletions at the third exon of OsRR22 and conferred a high level of salinity tolerance. Homozygous transgene-free progeny were identified via segregation in the T2 generation, with osrr22 showing similar agronomic performance to wild-type (733S and HZ). Furthermore, these two osrr22 lines were used to develop a new promising third-generation hybrid rice line with novel salinity tolerance. Overall, the results demonstrate that combining CRISPR/Cas9 targeted gene editing with the "third-generation hybrid rice system" approach allows for the efficient development of novel hybrid rice varieties that exhibit a high level of salinity tolerance, thereby ensuring improved cultivar stability and enhanced rice productivity.

Effect of Irrigation Management and Water Quality on Soil and Sorghum bicolor Payenne Yield in Cape Verde

Treated water use for agriculture will promote sustainable irrigation development and food sovereignty. The aim of this study is to assess the feasibility of subsurface drip irrigation (SDI) compared to drip irrigation (DI) and of reclaimed water (RW) versus conventional groundwater (CW), to produce forage sustainably in a warm arid region. A sorghum experiment was conducted in a field on Santiago Island (Cape Verde). A forage yield of 200 t fresh matter·ha−1·year−1, irrigated by RW, was obtained. Considering Cape Verde regulations, it is possible to irrigate sorghum using a drip system and RW without adding fertilizers. Soil fertility (OM and Ntot) increased, while risk parameters (EC, nitrate, and Na) returned to their initial values after the rainy season. The best irrigation water use efficiency was obtained by RWSDI (200 L·kg−1 DM) compared to RWDI, which needed 34% more water. According to the results, a high nitrate elimination rate in treatment plants might not be desirable if agricultural reuse is planned to irrigate high-N-demanding species. Establishing new salinity tolerance levels under reuse conditions with SDI, and irrigating in rainy months to promote the lixiviation of salts in arid regions are also necessary.

A comparative study on salt stress response of Camelina sativa and Carthamus tinctorius during germination

Soil salinization is one of the most significant global problems, leading to reduced agricultural productivity potential and biodiversity. The main salt commonly found on the surface of soils and in water is NaCl, which directly impacts plant growth and land degradation. Therefore, this study was conducted to examine the morpho-physiological characteristics of two genotypes of Camelina sativa (?NS Slatka?; ?NS Zlatka?) and two genotypes of Carthamus tinctorius (?NS Lana?; ?NS Una?), which potentially characterize them as salt-tolerant crops. The levels of salinity tolerance were compared under five NaCl treatments, ranging from 0 mM to 200 mM. Based on the obtained results, seeds of all four genotypes germinated at the highest salt concentration (200mM NaCl), but the germination percentage declined at all salt concentrations. Moreover, lower salt concentrations induced root elongation and reduced shoot length of seedlings of all four genotypes. Salt stress tolerance indexes showed the importance of converting the plant parameters into mathematical indexes, and the significance of comparing all the tolerance indexes according to salt stress.

Mitigation of salinity stress in barley genotypes with variable salt tolerance by application of zinc oxide nanoparticles.

Salinity has become a major environmental concern of agricultural lands, impairing crop production. The current study aimed to examine the role of zinc oxide nanoparticles (ZnO NPs) in reducing the oxidative stress induced by salinity and the overall improvement in phytochemical properties in barley. A total of nine different barley genotypes were first subjected to salt (NaCl) stress in hydroponic conditions to determine the tolerance among the genotypes. The genotype Annora was found as most sensitive, and the most tolerant genotype was Awaran 02 under salinity stress. In another study, the most sensitive (Annora) and tolerant (Awaran 02) barley genotypes were grown in pots under salinity stress (100 mM). At the same time, half of the pots were provided with the soil application of ZnO NPs (100 mg kg–1), and the other half pots were foliar sprayed with ZnO NPs (100 mg L–1). Salinity stress reduced barley growth in both genotypes compared to control plants. However, greater reduction in barley growth was found in Annora (sensitive genotype) than in Awaran 02 (tolerant genotype). The exogenous application of ZnO NPs ameliorated salt stress and improved barley biomass, photosynthesis, and antioxidant enzyme activities by reducing oxidative damage caused by salt stress. However, this positive effect by ZnO NPs was observed more in Awaran 02 than in Annora genotype. Furthermore, the foliar application of ZnO NPs was more effective than the soil application of ZnO NPs. Findings of the present study revealed that exogenous application of ZnO NPs could be a promising approach to alleviate salt stress in barley genotypes with different levels of salinity tolerance.

Seed Halopriming Improves Salinity Tolerance of Some Rice Cultivars During Seedling Stage

BackgroundSaline land in coastal areas has great potential for crop cultivation. Improving salt tolerance in rice is a key to expanding the available area for its growth and thus improving global food security. Seed priming with salt (halopriming) can enhance plant growth and decrease saline intolerance under salt stress conditions during the subsequent seedling stage. However, there is little known about rice defense mechanisms against salinity at seedling stages after seed halopriming treatment. This study focused on the effect of seed halopriming treatment on salinity tolerance in a susceptible cultivar, IR 64, a resistant cultivar, Pokkali, and two pigmented rice cultivars, Merah Kalimantan Selatan (Merah Kalsel) and Cempo Ireng Pendek (CI Pendek). We grew these cultivars in hydroponic culture, with and without halopriming at the seed stage, under either non-salt or salt stress conditions during the seedling stage.ResultsThe SES scoring assessment showed that the level of salinity tolerance in susceptible cultivar, IR 64, and moderate cultivar, Merah Kalsel, improved after seed halopriming treatment. Furthermore, seed halopriming improved the growth performance of IR 64 and Merah Kalsel rice seedlings. Quantitative PCR revealed that seed halopriming induced expression of the OsNHX1 and OsHKT1 genes in susceptible rice cultivar, IR 64 and Merah Kalsel thereby increasing the level of resistance to salinity. The expression levels of OsSOS1 and OsHKT1 genes in resistant cultivar, Pokkali, also increased but there was no affect on the level of salinity tolerance. On the contrary, seed halopriming decreased the expression level of OsSOS1 genes in pigmented rice cultivar, CI Pendek, but did not affect the level of salinity tolerance. The transporter gene expression induction significantly improved salinity tolerance in salinity-susceptible rice, IR 64, and moderately tolerant rice cultivar, Merah Kalsel. Induction of expression of the OsNHX1 and OsHKT1 genes in susceptible rice, IR 64, after halopriming seed treatment balances the osmotic pressure and prevents the accumulation of toxic concentrations of Na+, resulting in tolerance to salinity stress.ConclusionThese results suggest that seed halopriming can improve salinity tolerance of salinity-susceptible and moderately tolerant rice cultivars.

Salinity impacts on irrigation water-scarcity in food bowl regions of the US and Australia

Irrigation water use and crop production may be severely limited by both water shortages and increased salinity levels. However, impacts of crop-specific salinity limitations on irrigation water scarcity are largely unknown. We develop a salinity-inclusive water scarcity framework for the irrigation sector, accounting for crop-specific irrigation water demands and salinity tolerance levels and apply it to 29 sub-basins within two food bowl regions; the Central Valley (CV) (California) and the Murray–Darling basin (MDB) (Australia). Our results show that severe water scarcity (levels >0.4) occurs in 23% and 66% of all instances (from >17 000 monthly crop-specific estimates) for the CV and MDB, respectively. The highest water scarcity levels for both regions occurred during their summer seasons. Including salinity and crop-specific salinity tolerance levels further increased water scarcity levels, compared to estimations based on water quantity only, particularly at local sub-basin scales. We further investigate the potential of alleviating water scarcity through diluting surface water with lower saline groundwater resources, at instances where crop salinity tolerance levels are exceeded (conjunctive water use). Results from the CV highlights that conjunctive water use can reduce severe water scarcity levels by up to 67% (from 946 monthly instances where surface water salinity tolerance levels were exceeded). However, groundwater dilution requirements frequently exceed renewable groundwater rates, posing additional risks for groundwater depletion in several sub-basins. By capturing the dynamics of both crops, salinity and conjunctive water use, our framework can support local-regional agricultural and water management impacts, on water scarcity levels.

Somatic Embryos Induction of East Kalimantan Local Rice (Oryza sativa L.) Cultivars and In Vitro Selection Against Salinity

Soil salinity is one major environmental constraint on rice production, especially in coastal areas. The development of salt-tolerant genotypes is considered to be the most effective breeding strategy to overcome the constraint. This study aims to induce somatic embryos formation of East Kalimantan local rice cultivars and to obtain tolerant somatic embryos under saline condition via in vitro selection. Four commonly cultivated local rice cultivars, namely Buyung, Siam, Ketalun Tawar and Serai Gunung, were used in this study. The somatic embryos were produced using three different plant growth regulator (PGR) compositions. The salinity tolerance level of somatic embryos was induced by in vitro selection in salt toxicity medium containing 0 mM; 50 mM; 100 mM; 150 mM; 200 mM NaCl. The best medium for somatic embryogenesis contains 1 mg/l 2,4-D + 0.5 m/l BAP, resulting the highest percentage of cream and white non-compact callus on the tested cultivars. More than 70% of the somatic embryos were tolerant against salinity (NaCl 200 mM). However, only somatic embryos derived from Serai Gunung could regenerate into normal plantlets.

The effect of salinity stress on germination parameters in Satureja thymbra L. (Lamiaceae)

Salinity is an important problem all over the world. The destructive effect of salinity is observed from the seed germination stage. In this study, it was aimed to determine the effect of salinity on seed germination of the medically important Satureja thymbra L., whether pre-treatments are a factor in breaking the salinity stress, and to determine the level of salinity tolerance of this species. In the research, firstly, the seeds were exposed to two pre-treatments (80°C (5 minutes) + 10 ppm GA3 (24 hours), 80°C (5 minutes) + 100 ppm GA3 (24 hours)) and then 8 different NaCl concentrations (0.1 g/l, 1 g/l, 2.5 g/l, 5 g/l, 7.5 g/l,10 g/l, 15 g/l and 30 g/l) were tried. Germination seeds were counted every day and the effects of salinity on germination characteristics were investigated. The highest germination percentage (90%) was obtained at 0.1 g/l NaCl after 80°C (5 min.) + 100 ppm GA3 (24 h.) pre-treatment. The results showed that the effect of salinity was significant on germination parameters in p < 0.05. Obtained results showed that the highest NaCl concentration at which Satureja thymbra seed could germinate was 10 g/l.

Tolerance and Recovery Capacity to Reclaimed Wastewater Irrigation of Salvia officinalis and Asteriscus maritimus Plants Inoculated with Arbuscular Mycorrhizae

This work attempts to identify which of two species with different levels of salinity tolerance, Salvia officinalis L. or Asteriscus maritimus L., is more suitable for irrigation with reclaimed wastewater, as well as the effect of the arbuscular mycorrhiza Glomus iranicum on the plant. The experiment was carried out in a growth chamber with a first phase, where both species were irrigated with good quality water, a second phase in which the plants were irrigated with reclaimed wastewater, and a third phase in which the plants were irrigated with good quality water again (recovery). Salinity caused a reduction in leaf water potential, stomatal conductance and net photosynthesis in both species. The percentage of mycorrhization was higher in Asteriscus than in Salvia, mitigating the decrease in leaf water potential. There was osmotic adjustment in Salvia, although the proline content increased in both species. The damages produced were clearer in Salvia, in which lipid peroxidation values were higher. Likewise, the visual appearance of the leaves showed symptoms of toxicity in this species, although the mycorrhizae diminished these effects. Irrigation with good quality water induced the recovery of lipid peroxidation in both species, as well as the appearance of new leaves in Salvia.

Mining and utilization of salinity tolerant legumes in tropical coastal agroecosystems: An overview

Coastal saline soils are increasing year by year caused by climate change and human activities. Most of the coastal saline soils are idle due to their high salinity level and few crops can grow normally. Salinity tolerant legumes are naturally salinity tolerant, which can ecological cover the coastal saline soil, enhance soil fertility by symbiotic nitrogen fixation and increase the smallholder farmers’ benefits in terms of forage, green manure, food or medicine. However, few reports are available for the systematic evaluation of salinity tolerant legumes. This review summarizes and evaluates currently available salinity tolerant legume species that could potentially be used and discusses their potential for integration into smallholder mixed coastal systems of the Asia-Pacific region. 44 salinity tolerant legumes were summarized, 6 of them showed a high level of salinity tolerance, 17 of them showed a moderate level of salinity tolerance and 21 of them showed potential salinity tolerance but need be further proved. Many gaps such as combined tolerance evaluation, nitrogen fixation efficiency, animals feeding experiments and salinity tolerant rhizobia screening/inoculants were existed. Case studies demonstrate legumes could be used to reclaim coastal saline soils, but commitment and support from government and public services are necessary to address both seed system and extension needs, through the provision of adequate incentives, policies and development efforts.